Thermionic valve circuits



March 14, 1950 ANTALEK 2,500,504

THERMIONIC VALVE CIRCUITS Filed April 23, 1945 2 Sheets-Sheet 1 Fig.1.,

INTERMEDMTE DETECTOR TO MIXER fig iv g H21 AUDIO UTILIZATION Cmcun" l a was 2 L AMPL FIER ZLD Aumo FREQUENCY AMPLIFIER INVENTOR ATTORNEY March 14, 1950 J. J. ANTALEK 2,500,504

T'HERMIONIC VALVE cmcuns Filed April 23, 1945 v 2 Sheets-Sheet 2 DETECTOR at AUDIO FREQ AMPUFIER 2' AUDIO FREQ- AMPLlFIER INT. FREQ. AMPUFIER -.--wv A OSCILLATOR CRYSTAL CALIBRATION MIXER TUBE INVENTOR.

JOHN J ANTALEK ATTORNEY Patented Mar. 14, 1950 THERMIONIC VALVE CIRCUITS John J. Antalek, Chicago, 111., assignor to. The

Rauland Corporation, Chicago, 111., a corporation of Illinois Application April -23, 1945, Serial hi0. 589,784

9 Claims.

1 This invention relates to thermionic valve circuits and especially to amplifier circuits supplying a dial illuminating device or any other discontinuously operative device to permit at any desired moment accurate control of the amplified frequency or any other characteristic of the circuit.

One of the difficulties encountered in dial illumination is that the dial lamp requires a relatively large amount of current which not only weighs heavily on the life of the voltage source or battery in battery-supplied amplifier circuits but also, when switched on, is liable to produce a voltage drop deteriorating the quality and quantity of amplification.

A specific object of this invention is an audio amplification stage including several electron paths arranged in parallel, each path being fed by a filament. The filaments are arranged in parallel to a source of voltage such as a storage stages, the interference caused by intermittently switching off an electron path, or at least a portion thereof, and its replacement by a dial lamp have been found to cause a minimum of .noticeable amplitude of output. The life of the battery interference with frequency and remains practically unimpaired.

A more specific object of the invention is an audio amplifier stage comprising a single amplifier valve containing in addition to grid and anode a filament having two portions, each of these portions being connected in parallel to the voltage source. Loss in amplification in such a tube when operated with only one filament has been found to be negligible.

Another object of the invention is a radio frequency receiver comprising one or more amplification stages, the filament circuits of which are connected in parallel to a source of voltage and which includes one filament circuit connected to be selectively replaced by the filament circuit of another discontinuously operative 'tube, such, as the oscillator tube of a crystal calibrator.

This and other objects of the. invention are schematically illustrated in the accompanying drawings in which:

Fig. 1 shows a diagram of part of a superheterodyne radio receiver embodying the invention as applied to a dial lamp;

Fig. 2 shows a diagram of a radio frequency receiver embodying the invention as applied to theoscillator tube of a crystal calibrator.

In Fig. 1, the incoming high frequency oscillations, if necessary after sufficient amplification (not shown), are applied to grid I and mixedv with the oscillations produced at grid 2 of a mixer tube 3 consisting of a hexode. The anode of tube; 3 is connected, in a manner not shown, to the grid of. intermediate frequency amplifier 4, the. output of which is detected and amplified in tube 5 and further amplified in tube 6 which has a filament consisting of two half portions a. The output of tube 6 is. applied to a-utilization circuit. The filaments 9,, l0, H of tube 3,v 4, 5, respectively, and the filament halves l, 8 of tube 6 are connected in parallel. to storage battery l2. This battery can have any desired voltage, e. g. 6, 12 or 24 volts. In the present example each filamentis supplied by about 1.4 volts.

Connections and interconnections of tubes 3, 4, 5 and 6, which are not shown, are Well known in the art and can be made in any desired manner without exceeding the scope of this invention.

Push-button switch l3 substitutes the current of dial light [4; for one of the otherwise parallel half portions 1, 8' of the filament of valve 6. In the present example, valve 6 is a tube of the 3Q4 type which has two .050 amp. filaments. The: output from this tube is only very slightly reduced when one of the filament halves is not used. The dial light 14 is" also rated at about 1.4 volts at .050 amps. so that when the dial light is turnedon there is no increase in current drain through the voltage-dropping resistor l5 and, consequently, no change in filament voltage. If the-filament: voltage did change when the dial light was turned on, the H. F". oscillator circuit would, shiftin frequency as a result of the filament voltage: drop. This danger is: reduced to a minimum.

The: invention isv not.- limited to the circuit and circuit elements shown. or described. It. may be applied. with equal advantage:- to any other type of, thermionic; valve circuit" affording. dial illumination or any other discontinuous control function Instead of using: a" twin-filament. tube such as put circuit (not shown).

Another alternative is the provision of several.

tubes, especially of two tubes in parallel or pushpull connection and the replacement of the filament of one of these tubes by the filament of, a v

' discontinuously operative tube, such as a dial lamp or any other control tube.

Fig. 2 shows diagrammatically a radio frequency receiver in which antenna 21 is coupled over transformer 28 and tuning circuit 29 to the control grid of mixer tube 30. The anode of tube 30 is connected over transformer 3| to the input circuit of an intermediate fre'quency am plifier 32, the output of which is fed over transformer 33, a combined detector, and first audio frequency amplifier tube 34 to a second audio frequency amplifier tube "35 which, in turn, is connected over transformer 36 to a suitable out- Ihe filaments 31, 38, 39, 40 and 4| of tubes'3ll, 32, 34 and 35 are connected in parallel to battery terminals +A, -A. One of the filaments, 40, constituting half of the entire filament of tube 35, is connected to battery terminals +A, A over switch 46. The anode circuit of the intermediate frequency amplifier tube 32 is connected to the output circuit of oscillator tube 42 over oscillating circuit 43..

The grid circuit of tube 42 is controlled by crystal 44 in a conventional manner. The filament 45 of oscillator tube 42 is supplied. by battery terminals +A, A over the same switch 4 l'which, according to its position, heats either filament- 40 or filament 45, thus permitting frequency calibration without noticeably affecting the amplification of the receiver.

What I claim is:

In a thermionic valve circuit connected for continuous operation, a source of voltage, a number of electron-emitting means connected in parallel to the source, discontinuously operative means for controlling the operation of the circult at the desired moment, the controlling means. being connectable in parallel to the source and to one of said electron-emitting means, and switching means for selectively interchanging the controlling means for only a portion of said one electron-emitting means.

, 2. In a thermionic valve circuit connected for continuo s. operation, a source of voltage, a'number of electron-emitting means connecting in parallel to the source, frequency-calibrating means connectable in parallel to the source and tov one of the electron-emitting means, and switching means for selectively interchanging the frequency-calibrating means for at least a portion of said one electron-emitting means.

3. ma thermionic valve circuit; a source of voltage, a number of filaments, at least one of them consisting of two series-connected halves, each of said halves and the remainder of said filaments being connected in parallel to the source, high frequency calibrating means including a crystal-controlled oscillating tube, the tube having a filament, and switching means in one position adapted to connect the filament of the tube in parallel to the source as well as to one of said filament halves and in another position 4 to interchange the tube filament for the other filament half.

4. In a circuit according to claim 1, means controlled by audio frequency currents and controlling the electrons of at least some of the electron-emitting means.

5. Ina circuit according to claim 1, means ;controlled by audio modulated high frequency oscillations and controlling the electrons of one of said electron-emitting means, including a pentagrid mixer tube having one grid for applying'the audio modulated high frequency oscillations, at second grid for applying predetermined high frequency oscillations, an anode circuit for deriving high frequency oscillations of an intermediate frequency, means for amplifying the intermediate frequency oscillations, means for detecting the intermediate frequency oscillations, and means foramplifying the detected oscillations, the mixing means, the intermediate frequency amplifying means, the detecting means frequency amplifying means, combined detecting and audio amplifying means, audio amplifying means, each of said means including at least one electron-emitting filament, the audio frequency amplifying means including an electronemitting filament consisting of two series-connected halves, voltage-supplying means, said filaments and each of the filament halves being connectable in parallel to said voltage-supplying means, high frequency calibrating means including crystal-controlled oscillating means having an electron-emitting filament, a pushbutton switch, and means including said pushbutton switch for selectively either connecting said latter filament to and disconnecting one of said filament halves from said voltage-supplying means, or disconnecting said latter filament from and connecting one filament half to said voltagesupplying means.

7. In a thermionic valve circuit, an amplifying valve comprising a filament having a center tap to form two halves, a control valve having a filament, a source of current connectable in parallel to each half and the control valve filament, and switching means for selectively either connecting the valve filament and disconnecting one half from the source, or disconnecting the battery connectable in parallel to each half and the oscillator j filament, and a switch for selectively either opening connection between one half and source and simultaneously closing con- JOHN J. ANTALEK.

REFERENCES CITED The following references are of record. in the file of this patent:

UNITED STATES PATENTS Number Name Date Wold July 17, 1923 Pruden Aug. 5, 1924 Robinson et a1 May 27, 1928 Toomey Apr. 17, 1928 Ballantine Dec. 1, 1931 Wexler Apr. 19, 1932 Holst May 9, 1939 I-Iipsley Mar. 25, 1941 Baker Apr. 18, 1944 

